1.20: Book XX
ULYSSES CANNOT SLEEP—PENELOPE’S PRAYER TO DIANA—THE TWO SIGNS FROM HEAVEN—EUMAEUS AND PHILOETIUS ARRIVE—THE SUITORS DINE—CTESIPPUS THROWS AN OX’S FOOT AT ULYSSES—THEOCLYMENUS FORETELLS DISASTER AND LEAVES THE HOUSE.
Ulysses slept in the cloister upon an undressed bullock’s hide, on the top of which he threw several skins of the sheep the suitors had eaten, and Eurynome 156 threw a cloak over him after he had laid himself down. There, then, Ulysses lay wakefully brooding upon the way in which he should kill the suitors; and by and by, the women who had been in the habit of misconducting themselves with them, left the house giggling and laughing with one another. This made Ulysses very angry, and he doubted whether to get up and kill every single one of them then and there, or to let them sleep one more and last time with the suitors.
Thus he chided with his heart, and checked it into endurance, but he tossed about as one who turns a paunch full of blood and fat in front of a hot fire, doing it first on one side and then on the other, that he may get it cooked as soon as possible, even so did he turn himself about from side to side, thinking all the time how, single handed as he was, he should contrive to kill so large a body of men as the wicked suitors. But by and by Minerva came down from heaven in the likeness of a woman, and hovered over his head saying, “My poor unhappy man, why do you lie awake in this way? This is your house: your wife is safe inside it, and so is your son who is just such a young man as any father may be proud of.”
“Goddess,” answered Ulysses, “all that you have said is true, but I am in some doubt as to how I shall be able to kill these wicked suitors single handed, seeing what a number of them there always are. And there is this further difficulty, which is still more considerable. Supposing that with Jove’s and your assistance I succeed in killing them, I must ask you to consider where I am to escape to from their avengers when it is all over.”
“For shame,” replied Minerva, “why, any one else would trust a worse ally than myself, even though that ally were only a mortal and less wise than I am. Am I not a goddess, and have I not protected you throughout in all your troubles?
As she spoke she shed sleep over his eyes, and then went back to Olympus.
While Ulysses was thus yielding himself to a very deep slumber that eased the burden of his sorrows, his admirable wife awoke, and sitting up in her bed began to cry. When she had relieved herself by weeping she prayed to Diana saying, “Great Goddess Diana, daughter of Jove, drive an arrow into my heart and slay me; or let some whirlwind snatch me up and bear me through paths of darkness till it drop me into the mouths of over-flowing Oceanus, as it did the daughters of Pandareus. The daughters of Pandareus lost their father and mother, for the gods killed them, so they were left orphans. But Venus took care of them, and fed them on cheese, honey, and sweet wine. Juno taught them to excel all women in beauty of form and understanding; Diana gave them an imposing presence, and Minerva endowed them with every kind of accomplishment; but one day when Venus had gone up to Olympus to see Jove about getting them married (for well does he know both what shall happen and what not happen to every one) the storm winds came and spirited them away to become handmaids to the dread Erinyes. Even so I wish that the gods who live in heaven would hide me from mortal sight, or that fair Diana might strike me, for I would fain go even beneath the sad earth if I might do so still looking towards Ulysses only, and without having to yield myself to a worse man than he was. Besides, no matter how much people may grieve by day, they can put up with it so long as they can sleep at night, for when the eyes are closed in slumber people forget good and ill alike; whereas my misery haunts me even in my dreams. This very night methought there was one lying by my side who was like Ulysses as he was when he went away with his host, and I rejoiced, for I believed that it was no dream, but the very truth itself.”
On this the day broke, but Ulysses heard the sound of her weeping, and it puzzled him, for it seemed as though she already knew him and was by his side. Then he gathered up the cloak and the fleeces on which he had lain, and set them on a seat in the cloister, but he took the bullock’s hide out into the open. He lifted up his hands to heaven, and prayed, saying “Father Jove, since you have seen fit to bring me over land and sea to my own home after all the afflictions you have laid upon me, give me a sign out of the mouth of some one or other of those who are now waking within the house, and let me have another sign of some kind from outside.”
Thus did he pray. Jove heard his prayer and forthwith thundered high up among the clouds from the splendour of Olympus, and Ulysses was glad when he heard it. At the same time within the house, a miller-woman from hard by in the mill room lifted up her voice and gave him another sign. There were twelve miller-women whose business it was to grind wheat and barley which are the staff of life. The others had ground their task and had gone to take their rest, but this one had not yet finished, for she was not so strong as they were, and when she heard the thunder she stopped grinding and gave the sign to her master. “Father Jove,” said she, “you, who rule over heaven and earth, you have thundered from a clear sky without so much as a cloud in it, and this means something for somebody; grant the prayer, then, of me your poor servant who calls upon you, and let this be the very last day that the suitors dine in the house of Ulysses. They have worn me out with labour of grinding meal for them, and I hope they may never have another dinner anywhere at all.”
Ulysses was glad when he heard the omens conveyed to him by the woman’s speech, and by the thunder, for he knew they meant that he should avenge himself on the suitors.
Then the other maids in the house rose and lit the fire on the hearth; Telemachus also rose and put on his clothes. He girded his sword about his shoulder, bound his sandals on to his comely feet, and took a doughty spear with a point of sharpened bronze; then he went to the threshold of the cloister and said to Euryclea, “Nurse, did you make the stranger comfortable both as regards bed and board, or did you let him shift for himself?—for my mother, good woman though she is, has a way of paying great attention to second-rate people, and of neglecting others who are in reality much better men.”
“Do not find fault child,” said Euryclea, “when there is no one to find fault with. The stranger sat and drank his wine as long as he liked: your mother did ask him if he would take any more bread and he said he would not. When he wanted to go to bed she told the servants to make one for him, but he said he was such a wretched outcast that he would not sleep on a bed and under blankets; he insisted on having an undressed bullock’s hide and some sheepskins put for him in the cloister and I threw a cloak over him myself.” 157
Then Telemachus went out of the court to the place where the Achaeans were meeting in assembly; he had his spear in his hand, and he was not alone, for his two dogs went with him. But Euryclea called the maids and said, “Come, wake up; set about sweeping the cloisters and sprinkling them with water to lay the dust; put the covers on the seats; wipe down the tables, some of you, with a wet sponge; clean out the mixing-jugs and the cups, and go for water from the fountain at once; the suitors will be here directly; they will be here early, for it is a feast day.”
Thus did she speak, and they did even as she had said: twenty of them went to the fountain for water, and the others set themselves busily to work about the house. The men who were in attendance on the suitors also came up and began chopping firewood. By and by the women returned from the fountain, and the swineherd came after them with the three best pigs he could pick out. These he let feed about the premises, and then he said good-humouredly to Ulysses, “Stranger, are the suitors treating you any better now, or are they as insolent as ever?”
“May heaven,” answered Ulysses, “requite to them the wickedness with which they deal high-handedly in another man’s house without any sense of shame.”
Thus did they converse; meanwhile Melanthius the goatherd came up, for he too was bringing in his best goats for the suitors’ dinner; and he had two shepherds with him. They tied the goats up under the gatehouse, and then Melanthius began gibing at Ulysses. “Are you still here, stranger,” said he, “to pester people by begging about the house? Why can you not go elsewhere? You and I shall not come to an understanding before we have given each other a taste of our fists. You beg without any sense of decency: are there not feasts elsewhere among the Achaeans, as well as here?”
Ulysses made no answer, but bowed his head and brooded. Then a third man, Philoetius, joined them, who was bringing in a barren heifer and some goats. These were brought over by the boatmen who are there to take people over when any one comes to them. So Philoetius made his heifer and his goats secure under the gatehouse, and then went up to the swineherd. “Who, Swineherd,” said he, “is this stranger that is lately come here? Is he one of your men? What is his family? Where does he come from? Poor fellow, he looks as if he had been some great man, but the gods give sorrow to whom they will—even to kings if it so pleases them.”
As he spoke he went up to Ulysses and saluted him with his right hand; “Good day to you, father stranger,” said he, “you seem to be very poorly off now, but I hope you will have better times by and by. Father Jove, of all gods you are the most malicious. We are your own children, yet you show us no mercy in all our misery and afflictions. A sweat came over me when I saw this man, and my eyes filled with tears, for he reminds me of Ulysses, who I fear is going about in just such rags as this man’s are, if indeed he is still among the living. If he is already dead and in the house of Hades, then, alas! for my good master, who made me his stockman when I was quite young among the Cephallenians, and now his cattle are countless; no one could have done better with them than I have, for they have bred like ears of corn; nevertheless I have to keep bringing them in for others to eat, who take no heed to his son though he is in the house, and fear not the wrath of heaven, but are already eager to divide Ulysses’ property among them because he has been away so long. I have often thought—only it would not be right while his son is living—of going off with the cattle to some foreign country; bad as this would be, it is still harder to stay here and be ill-treated about other people’s herds. My position is intolerable, and I should long since have run away and put myself under the protection of some other chief, only that I believe my poor master will yet return, and send all these suitors flying out of the house.”
“Stockman,” answered Ulysses, “you seem to be a very well-disposed person, and I can see that you are a man of sense. Therefore I will tell you, and will confirm my words with an oath. By Jove, the chief of all gods, and by that hearth of Ulysses to which I am now come, Ulysses shall return before you leave this place, and if you are so minded you shall see him killing the suitors who are now masters here.”
“If Jove were to bring this to pass,” replied the stockman, “you should see how I would do my very utmost to help him.”
And in like manner Eumaeus prayed that Ulysses might return home.
Thus did they converse. Meanwhile the suitors were hatching a plot to murder Telemachus: but a bird flew near them on their left hand—an eagle with a dove in its talons. On this Amphinomus said, “My friends, this plot of ours to murder Telemachus will not succeed; let us go to dinner instead.”
The others assented, so they went inside and laid their cloaks on the benches and seats. They sacrificed the sheep, goats, pigs, and the heifer, and when the inward meats were cooked they served them round. They mixed the wine in the mixing-bowls, and the swineherd gave every man his cup, while Philoetius handed round the bread in the bread baskets, and Melanthius poured them out their wine. Then they laid their hands upon the good things that were before them.
Telemachus purposely made Ulysses sit in the part of the cloister that was paved with stone; 158 he gave him a shabby looking seat at a little table to himself, and had his portion of the inward meats brought to him, with his wine in a gold cup. “Sit there,” said he, “and drink your wine among the great people. I will put a stop to the gibes and blows of the suitors, for this is no public house, but belongs to Ulysses, and has passed from him to me. Therefore, suitors, keep your hands and your tongues to yourselves, or there will be mischief.”
The suitors bit their lips, and marvelled at the boldness of his speech; then Antinous said, “We do not like such language but we will put up with it, for Telemachus is threatening us in good earnest. If Jove had let us we should have put a stop to his brave talk ere now.”
Thus spoke Antinous, but Telemachus heeded him not. Meanwhile the heralds were bringing the holy hecatomb through the city, and the Achaeans gathered under the shady grove of Apollo.
Then they roasted the outer meat, drew it off the spits, gave every man his portion, and feasted to their heart’s content; those who waited at table gave Ulysses exactly the same portion as the others had, for Telemachus had told them to do so.
But Minerva would not let the suitors for one moment drop their insolence, for she wanted Ulysses to become still more bitter against them. Now there happened to be among them a ribald fellow, whose name was Ctesippus, and who came from Same. This man, confident in his great wealth, was paying court to the wife of Ulysses, and said to the suitors, “Hear what I have to say. The stranger has already had as large a portion as any one else; this is well, for it is not right nor reasonable to ill-treat any guest of Telemachus who comes here. I will, however, make him a present on my own account, that he may have something to give to the bath-woman, or to some other of Ulysses’ servants.”
As he spoke he picked up a heifer’s foot from the meat-basket in which it lay, and threw it at Ulysses, but Ulysses turned his head a little aside, and avoided it, smiling grimly Sardinian fashion 159 as he did so, and it hit the wall, not him. On this Telemachus spoke fiercely to Ctesippus, “It is a good thing for you,” said he, “that the stranger turned his head so that you missed him. If you had hit him I should have run you through with my spear, and your father would have had to see about getting you buried rather than married in this house. So let me have no more unseemly behaviour from any of you, for I am grown up now to the knowledge of good and evil and understand what is going on, instead of being the child that I have been heretofore. I have long seen you killing my sheep and making free with my corn and wine: I have put up with this, for one man is no match for many, but do me no further violence. Still, if you wish to kill me, kill me; I would far rather die than see such disgraceful scenes day after day—guests insulted, and men dragging the women servants about the house in an unseemly way.”
They all held their peace till at last Agelaus son of Damastor said, “No one should take offence at what has just been said, nor gainsay it, for it is quite reasonable. Leave off, therefore, ill-treating the stranger, or any one else of the servants who are about the house; I would say, however, a friendly word to Telemachus and his mother, which I trust may commend itself to both. ‘As long,’ I would say, ‘as you had ground for hoping that Ulysses would one day come home, no one could complain of your waiting and suffering 160 the suitors to be in your house. It would have been better that he should have returned, but it is now sufficiently clear that he will never do so; therefore talk all this quietly over with your mother, and tell her to marry the best man, and the one who makes her the most advantageous offer.
To this Telemachus answered, “By Jove, Agelaus, and by the sorrows of my unhappy father, who has either perished far from Ithaca, or is wandering in some distant land, I throw no obstacles in the way of my mother’s marriage; on the contrary I urge her to choose whomsoever she will, and I will give her numberless gifts into the bargain, but I dare not insist point blank that she shall leave the house against her own wishes. Heaven forbid that I should do this.”
Minerva now made the suitors fall to laughing immoderately, and set their wits wandering; but they were laughing with a forced laughter. Their meat became smeared with blood; their eyes filled with tears, and their hearts were heavy with forebodings. Theoclymenus saw this and said, “Unhappy men, what is it that ails you? There is a shroud of darkness drawn over you from head to foot, your cheeks are wet with tears; the air is alive with wailing voices; the walls and roof-beams drip blood; the gate of the cloisters and the court beyond them are full of ghosts trooping down into the night of hell; the sun is blotted out of heaven, and a blighting gloom is over all the land.”
Thus did he speak, and they all of them laughed heartily. Eurymachus then said, “This stranger who has lately come here has lost his senses. Servants, turn him out into the streets, since he finds it so dark here.”
But Theoclymenus said, “Eurymachus, you need not send any one with me. I have eyes, ears, and a pair of feet of my own, to say nothing of an understanding mind. I will take these out of the house with me, for I see mischief overhanging you, from which not one of you men who are insulting people and plotting ill deeds in the house of Ulysses will be able to escape.”
He left the house as he spoke, and went back to Piraeus who gave him welcome, but the suitors kept looking at one another and provoking Telemachus by laughing at the strangers. One insolent fellow said to him, “Telemachus, you are not happy in your guests; first you have this importunate tramp, who comes begging bread and wine and has no skill for work or for hard fighting, but is perfectly useless, and now here is another fellow who is setting himself up as a prophet. Let me persuade you, for it will be much better to put them on board ship and send them off to the Sicels to sell for what they will bring.”
Telemachus gave him no heed, but sate silently watching his father, expecting every moment that he would begin his attack upon the suitors.
Meanwhile the daughter of Icarius, wise Penelope, had had a rich seat placed for her facing the court and cloisters, so that she could hear what every one was saying. The dinner indeed had been prepared amid much merriment; it had been both good and abundant, for they had sacrificed many victims; but the supper was yet to come, and nothing can be conceived more gruesome than the meal which a goddess and a brave man were soon to lay before them—for they had brought their doom upon themselves.


5.10: Reconstituted Medication
In the previous section, we calculated medication doses that were provided in a liquid form in a given concentration. Medications are also commonly supplied in dry form, such as powders or crystals, that must be reconstituted with fluid before they are administered parenterally by injection. Reconstitution is the process of adding a liquid diluent to a dry ingredient to make a specific concentration of liquid. See Figure \(\PageIndex{1}\) [1] for an example of a vial of medication that requires reconstitution. When reconstituting medications, it is important to follow the reconstitution instructions carefully so the medication is prepared in the correct concentration. When calculating the dosage of reconstituted medication to administer to the patient, the amount of fluid used to dilute the medication must also be considered. Let’s practice using dimensional analysis to determine how much of a reconstituted medication should be administered.
Practice Problem: Reconstituted Medication
Patient Information:
Name: Liam Vang, DOB: 04/04/19xx, Age 8, Allergies: NKDA, Weight: 60 kg
Provider Order: Cefazolin 500 mg IM every 8 hours
Medication Supplied: See Figure \(\PageIndex{2}\) [2] for the drug label of the medication as it is supplied.
- Start by reading the order and the drug label. Liam has an order to receive 500 mg of Cefazolin. The vial of medication in powder form states there are 500 mg per vial. The powder must be reconstituted before it can be administered. The reconstitution instructions on the label state to add 2 mL of sterile water to the vial to reconstitute the powder into a liquid form for injection. The label states that after the powder is reconstituted with the 2 mL of diluent, the concentration of fluid will be 225 mg/mL. See a close-up image of reconstitution instructions in Figure \(\PageIndex{3}\). [3]
When setting up the problem, we need to identify the correct information to include in the equation. There are several numbers we may be tempted to try to incorporate into our equation, such as 500 mg per vial, 2 mL diluent, and approximate volume of 2.2 mL. These are numbers specific to the reconstitution process. However, keep in mind that our final goal is to calculate the number of mL of fluid to administer after the medication is reconstituted, so this will be the goal unit. The other piece of important information that the drug label states is that the reconstituted medication will provide a concentration of 225 mg/mL.
2. Start by identifying the goal unit for which you are solving, which is mL to administer as an injection:
\[ mL~=~? \]
3. Set up the first fraction by matching the numerator to the goal unit of mL. In this problem, we know from the drug label that the known concentration of the reconstituted medication is 225 mg per mL, so add 1 mL to the numerator and 225 mg to the denominator:
\[ mL=\frac{1~mL}{225~mg} \]
4. Set up the second fraction with mg in the numerator with the intent to cross off mg diagonally. Look at the given information to determine how it relates to mg. The order tells us to give Liam 500 mg of the medication. Plug in 500 in the numerator of the second fraction with one in the denominator so that mg will cross off diagonally:
\[ mL=\frac{1~mL}{225~mg}~~\times~~\frac{500~mg}{1} \]
5. Cross off units diagonally. Multiply across the numerators and the denominators, and then divide the final fraction for the answer in mL:
\[ mL=\frac{1~mL}{225~\cancel{mg}}~~\times~~\frac{500~\cancel{mg}}{1}~~=~~\frac{500~mL}{225}~=~2.2222~mL \]
6. Because the patient is a child, round to hundredth for the final answer: 2.22 mL
Please practice medication reconstitution calculations with the following interactive learning activity.
Query \(\PageIndex{1}\)
- “ Zevtera 1Vial UK(3)(1)<PHONE_NUMBER>4).jpg ” by Mohamd Ghani is licensed under CC BY-SA 2.0 ↵
- “Cefazolin Label Fig. 9.PNG" by Jody Myhre-Oechsle, Chippewa Valley Technical College , Open RN is licensed under CC BY 4.0 ↵
- “Reconstitution Instructions.png" by Jody Myhre-Oechsle, Chippewa Valley Technical College , Open RN is licensed under CC BY 4.0 ↵
- Southwest Tech Math/Science Center. (2018, April 25). Entry-level drug calculations for nursing students part 3 – Pharmacology, nursing math *. [Video]. YouTube. All rights reserved. Video used with permission. https://youtu.be/g9nqo-aZuHE ↵
- RegisteredNurseRN. (2015, October 7). Dosage calculations made easy | Reconstitution calculation medication problems nursing students (10). [Video]. YouTube. All rights reserved. Video used with permission. https://youtu.be/TK3ZAaMuhYk ↵


18.4: Electric Field- Concept of a Field Revisited
Learning Objectives
By the end of this section, you will be able to:
- Describe a force field and calculate the strength of an electric field due to a point charge.
- Calculate the force exerted on a test charge by an electric field.
- Explain the relationship between electrical force ( F ) on a test charge and electrical field strength ( E ).
Contact forces, such as between a baseball and a bat, are explained on the small scale by the interaction of the charges in atoms and molecules in close proximity. They interact through forces that include the Coulomb force . Action at a distance is a force between objects that are not close enough for their atoms to “touch.” That is, they are separated by more than a few atomic diameters.
For example, a charged rubber comb attracts neutral bits of paper from a distance via the Coulomb force. It is very useful to think of an object being surrounded in space by a force field . The force field carries the force to another object (called a test object) some distance away.
Concept of a Field
A field is a way of conceptualizing and mapping the force that surrounds any object and acts on another object at a distance without apparent physical connection. For example, the gravitational field surrounding the earth (and all other masses) represents the gravitational force that would be experienced if another mass were placed at a given point within the field.
In the same way, the Coulomb force field surrounding any charge extends throughout space. Using Coulomb’s law, \(F=k|q_{1}q_{2}|/r^{2}\), its magnitude is given by the equation \(F=k|qQ|/r^{2}\), for a point charge (a particle having a charge \(Q\)) acting on a test charge \(q\) at a distance \(r\) (Figure \(\PageIndex{1}\)). Both the magnitude and direction of the Coulomb force field depend on \(Q\) and the test charge \(q\).
To simplify things, we would prefer to have a field that depends only on \(Q\) and not on the test charge \(q\). The electric field is defined in such a manner that it represents only the charge creating it and is unique at every point in space. Specifically, the electric field \(E\) is defined to be the ratio of the Coulomb force to the test charge:
\[\mathbf{E}=\dfrac{\mathbf{F}}{q},\]
where \(\mathbf{F}\) is the electrostatic force (or Coulomb force) exerted on a positive test charge \(q\). It is understood that \(\mathbf{E}\) is in the same direction as \(\mathbf{F}\). It is also assumed that \(q\) is so small that it does not alter the charge distribution creating the electric field. The units of electric field are newtons per coulomb (N/C). If the electric field is known, then the electrostatic force on any charge \(q\) is simply obtained by multiplying charge times electric field, or \(\mathbf{F}=q\mathbf{E}\). Consider the electric field due to a point charge \(Q\). According to Coulomb’s law, the force it exerts on a test charge \(q\) is \(F=k|qQ|/r^{2}\). Thus the magnitude of the electric field, \(E\), for a point charge is
\[E=|\dfrac{F}{q}|=k|\dfrac{qQ}{qr^{2}}|=k\dfrac{|Q|}{r^{2}}.\]
Since the test charge cancels, we see that
\[E=k\dfrac{|Q|}{r^{2}}.\]
The electric field is thus seen to depend only on the charge \(Q\) and the distance \(r\); it is completely independent of the test charge\(q\).
Example \(\PageIndex{1}\): Calculating the Electric Field of a Point Charge
Calculate the strength and direction of the electric field \(E\) due to a point charge of 2.00 nC (nano-Coulombs) at a distance of 5.00 mm from the charge.
Strategy
We can find the electric field created by a point charge by using the equation \(E=kQ/r^{2}\).
Solution
Here \(Q=2.00\times 10^{-9}C\) and \(r=5.00\times 10^{-3}m\). Entering those values into the above equation gives
\[ \begin{align*} E&=k\dfrac{Q}{r^{2}} \\[5pt] &= (8.99\times 10^{9} N\cdot m^{2}/C^{2})\times \dfrac{(2.00\times 10^{-9}C)}{(5.00\times 10^{-3}m)^{2}} \\[5pt] &= 7.19\times 10^{5} N/C. \end{align*}\]
Discussion
This electric field strength is the same at any point 5.00 mm away from the charge \(Q\) that creates the field. It is positive, meaning that it has a direction pointing away from the charge \(Q\).
Example \(\PageIndex{2}\): Calculating the Force Exerted on a Point Charge by an Electric Field
What force does the electric field found in the previous example exert on a point charge of\(-0.250\mu C\)?
Strategy
Since we know the electric field strength and the charge in the field, the force on that charge can be calculated using the definition of electric field \(\mathbf{E}=\mathbf{F}/q\) rearranged to \(\mathbf{F}=q\mathbf{E}\).
Solution
The magnitude of the force on a charge \(q=-.250\mu C\) exerted by a field of strength \(E=7.20\times 10^{5} N/C\) is thus,
\[ \begin{align*} F &=-qE \\[5pt] &= (0.250\times 10^{-6}C)(7.20\times 10^{5} N/C) \\[5pt] &=0.180N. \end{align*}\]
Because \(q\) is negative, the force is directed opposite to the direction of the field.
Discussion
The force is attractive, as expected for unlike charges. (The field was created by a positive charge and here acts on a negative charge.) The charges in this example are typical of common static electricity, and the modest attractive force obtained is similar to forces experienced in static cling and similar situations.
PHET EXPLORATIONS: ELECTRIC FIELD OF DREAMS
Play ball! Add charges to the Field of Dreams and see how they react to the electric field. Turn on a background electric field and adjust the direction and magnitude.
Summary
- The electrostatic force field surrounding a charged object extends out into space in all directions.
- The electrostatic force exerted by a point charge on a test charge at a distance\(r\) depends on the charge of both charges, as well as the distance between the two.
- The electric field \(\mathbf{E}\) is defined to be \(\mathbf{E}=\dfrac{\mathbf{F}}{q},\) where \(\mathbf{F}\) is the Coulomb or electrostatic force exerted on a small positive test charge \(q\). \(\mathbf{E}\) has units of N/C.
- The magnitude of the electric field \(\mathbf{E}\) created by a point charge \(Q\) is \(\mathbf{E}=k\dfrac{|Q|}{r^{2}}.\) where \(r\) is the distance from \(Q\). The electric field \(\mathbf{E}\) is a vector and fields due to multiple charges add like vectors.
Glossary
- field
- a map of the amount and direction of a force acting on other objects, extending out into space
- point charge
- A charged particle, designated Q, generating an electric field
- test charge
- A particle (designated q) with either a positive or negative charge set down within an electric field generated by a point charge


8: Solving Linear Equations
Teetering high above the floor, this amazing mobile remains aloft thanks to its carefully balanced mass. Any shift in either direction could cause the mobile to become lopsided, or even crash downward. In this chapter, we will solve equations by keeping quantities on both sides of an equal sign in perfect balance.
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- 8.1: Solve Equations Using the Subtraction and Addition Properties of Equality (Part 1)
- The purpose in solving an equation is to find the value or values of the variable that make each side of the equation the same. Any value of the variable that makes the equation true is called a solution to the equation. We can use the Subtraction and Addition Properties of Equality to solve equations by isolating the variable on one side of the equation. Usually, we will need to simplify one or both sides of an equation before using the Subtraction or Addition Properties of Equality.
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- 8.2: Solve Equations Using the Subtraction and Addition Properties of Equality (Part 2)
- In most of the application problems we solved earlier, we were able to find the quantity we were looking for by simplifying an algebraic expression. Now we will be using equations to solve application problems. We’ll start by restating the problem in just one sentence, assign a variable, and then translate the sentence into an equation to solve. When assigning a variable, choose a letter that reminds you of what you are looking for.
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- 8.3: Solve Equations Using the Division and Multiplication Properties of Equality
- We can also use the Division and Multiplication Properties of Equality to solve equations by isolating the variable on one side of the equation. The goal of using the Division and Multiplication Properties of Equality is to "undo" the operation on the variable. Usually, we will need to simplify one or both sides of an equation before using the Division or Multiplication Properties of Equality.
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- 8.4: Solve Equations with Variables and Constants on Both Sides (Part 1)
- You may have noticed that in all the equations we have solved so far, all the variable terms were on only one side of the equation with the constants on the other side. This does not happen all the time—so now we’ll see how to solve equations where the variable terms and/or constant terms are on both sides of the equation.
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- 8.5: Solve Equations with Variables and Constants on Both Sides (Part 2)
- Each of the first few sections of this chapter has dealt with solving one specific form of a linear equation. It’s time now to lay out an overall strategy that can be used to solve any linear equation. We call this the general strategy. Some equations won’t require all the steps to solve, but many will. Simplifying each side of the equation as much as possible first makes the rest of the steps easier.
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- 8.6: Solve Equations with Fraction or Decimal Coefficients
- The General Strategy for Solving Linear Equations can be used to solve for equations with fraction or decimal coefficients. Clearing the equation of fractions applies the Multiplication Property of Equality by multiplying both sides of the equation by the LCD of all fractions in the equation. The result of this operation will be a new equation, equivalent to the first, but with no fractions. When we have an equation with decimals, we can use the same process we used to clear fractions.
Figure 8.1 - A Calder mobile is balanced and has several elements on each side. (credit: paurian, Flickr)
Contributors and Attributions
-
Lynn Marecek (Santa Ana College) and MaryAnne Anthony-Smith (Formerly of Santa Ana College). This content is licensed under Creative Commons Attribution License v4.0 "Download for free at<EMAIL_ADDRESS>."


27.6: Impact of Adverse Childhood Experiences
By the end of this section, you should be able to:
- Define adverse childhood experiences (ACEs).
- Describe the health needs of individuals who have experienced ACEs.
- Examine how the health needs of individuals with ACEs intersect with the social determinants of health.
- Identify the nurse’s role in preventing ACEs and caring for those who have experienced ACEs.
Adverse childhood experiences (ACEs) are traumatic childhood events that can have a lifelong negative impact on health (CDC, 2021a; CDC 2022a). Traumatic events may include experiencing violence or neglect, witnessing violence in the home or community, or having a family member attempt or die by suicide. Growing up in an environment that undermines a sense of safety, stability, or bonding—for example, in a household with substance use or mental health problems, instability due to parental separation, or a family member being incarcerated—also contributes to ACEs (CDC, 2022a). ACEs create toxic stress , or the prolonged activation of the stress response system, which disrupts the development of brain architecture and increases the risk for stress-related disease and cognitive impairment (Figure 27.8) (Harvard University Center on the Developing Child [HUCDC], 2023). A normal positive stress response is characterized by short increases in heart rate and mild elevation in hormone levels, as occurs commonly when receiving an injection. A tolerable stress response results in a greater degree of activation of the body’s stress response due to a more severe obstacle, such as the loss of a loved one or a natural disaster. If the duration of activation is limited and supported by caring relationships with adults, the brain can recover. The toxic stress response occurs when the child experiences frequent and prolonged adversity such as abuse, neglect, caregiver mental illness, or the accrued burden of economic hardship without adequate caregiver support.
Toxic stress from ACEs negatively affects children’s developing brains, immune systems, and stress-response systems, in turn affecting their attention, decision-making, and learning abilities (CDC, 2022a). ACEs’ effects increase over time, impacting lifelong health and opportunities (CDC, 2021b). The more ACEs an individual experiences, the higher their ACE score, and the more at risk they become for various poor health outcomes. Associated with chronic health problems, mental illness, and substance use in adulthood, ACEs are entirely preventable. In the United States, 61 percent of adults have at least one ACE, and 16 percent, one out of every six adults, have four or more ACEs (CDC, 2021b). Females and racial and ethnic minority groups are at greater risk for experiencing four or more ACEs (CDC, 2021b).
Health Needs of Children Experiencing ACEs
ACEs are linked to chronic health problems such as heart disease, diabetes, COPD, asthma, cancer, depression, and substance use problems (CDC, 2022a). Five of the leading causes of death are associated with ACEs, with higher numbers correlated with higher risks for poor health outcomes (CDC, 2019a). Preventing ACEs could reduce many adverse health conditions. The CDC estimates that preventing ACEs could help alleviate up to 21 million cases of depression and almost 2 million cases of heart disease; a 10 percent reduction in ACEs could save 56 billion dollars (CDC, 2022a; CDC, 2023b). Evidence shows that preventing ACEs could also positively impact socioeconomic challenges, such as reducing the number of adults who are unemployed or who do not graduate high school (CDC, 2021b). Data suggest that the best way to address these health care needs is to prevent ACEs from occurring in the first place. For those who have already experienced ACEs, many interventions can help the individual recover from the trauma caused by the toxic stress (HUCDC, 2023a).
How ACEs Intersect with the Social Determinants of Health
ACEs intersect with the social determinants of health related to economic stability, education, neighborhood and built environment, and social and community context. Individuals living with economic insecurity or poverty are at increased risk of experiencing ACEs or exposing their children to ACEs. Child maltreatment is more common among families experiencing poverty (Hargreaves et al., 2019). Experiencing food insecurity, moving residences frequently, and generally living in under-resourced neighborhoods all contribute to ACEs and cause toxic stress. ACEs negatively impact education, job opportunities, and income potential, resulting in increased risks of injury, sexually transmitted infections, maternal and child health problems, and involvement in sex trafficking (CDC, 2022a). Children who grow up with toxic stress face many struggles throughout life, such as difficulty forming stable relationships, maintaining a job, and staying financially secure. Adults can pass these effects on to their children, who may face additional exposure to toxic stress from poverty resulting from limited opportunities (CDC, 2022a).
The Nurse’s Role in Caring for Children Experiencing ACEs
To prevent ACEs, nurses must understand and address factors that put individuals at risk for violence (CDC, 2022a). Creating a safe and stable environment for children and families, with healthy relationships, is essential to helping children reach their full potential. The CDC encourages communities to adopt and utilize their six strategies for preventing ACES (CDC, 2022a):
- Strengthen economic supports to families
- Promote social norms that protect against violence and adversity
- Ensure a strong start for children
- Teach skills
- Connect youth to caring adults and activities
- Intervene to lessen immediate and long-term harms
The CDC also recommends raising awareness of ACEs to help change their perception and shift the focus from individual responsibility to broader solutions. Reducing the stigma around seeking help for parenting challenges, substance misuse, depression, and suicidal thoughts is another community-level strategy. These steps help create safe and stable neighborhoods and communities where each child can thrive (CDC, 2022a). Primary prevention is best, but when this is not possible, community and public health nurses can work with clients to assist them in accessing mental health counseling and treatment specific to trauma. Nurses can also utilize a trauma-informed approach grounded in trust and building rapport with the client, acknowledging that trauma and harm have occurred and finding ways to engage these clients in necessary health care. Some studies have demonstrated that meditation and breathing exercises can assist clients in reducing the effects of toxic stress (HUCDC, 2023a). Nurses have a role in primary, secondary, and tertiary prevention of ACEs (Table 27.7).
| Primary prevention | |
| Prevent early trauma to improve adult health by reducing sources of stress (CDC, 2021b) | |
|
|
| Secondary prevention | |
| Identify clients with ACEs | |
|
|
| Tertiary prevention | |
| Reduce the impact ACEs have on health and promoting rehabilitation | |
|
|
Caring for vulnerable and disadvantaged populations and communities requires an interprofessional approach involving many community partners. It will take a concerted effort by health care professionals, government bodies, community organizations, school districts, and local and state policymakers to address the inequitable policies and discriminatory behaviors that affect disadvantaged populations. Nurses and other health care professionals have a major role to play in reducing health inequities in these populations. These professionals can work to change negative attitudes toward the disadvantaged, remove stigma, and advocate for more equitable policies to achieve health equity and social justice. Each of the six disadvantaged populations discussed in this chapter requires nurses who are caring, empathetic, and understanding of their unique lived experiences. Just as nurses should assess for the SDOH at every health encounter, nurses need to assess the lived experience of their clients and recognize that certain risk factors or characteristics place some individuals at inherent disadvantage.


3.3: The Accounting Entity
Learning Outcomes
- Define the accounting entity and discuss the going concern concept
What is the Accounting Concept of the Economic Entity?
One of the most basic underlying assumptions of GAAP is that there are boundaries around a business organization that define a single economic reporting entity. This may sound obvious at first, but in today’s complex business world, those boundaries aren’t always crystal clear. Another one of the fundamental principles of GAAP is that the economic entity, the business, is a going concern. In other words, it’s not in the midst of wrapping up its affairs.
Enron
Let’s revisit Enron as an example.
Enron started out as a legitimate business in 1985 when two relatively small pipeline companies, HNG and InterNorth, merged into one.
HNG was formed from the Houston Oil Co. in the 1920s and provided gas to retail customers in Houston. In 1976 it sold its retail gas business in Houston to concentrate on gas exploration and production and other businesses. By 1984 HNG had assets of $3.7 billion, sales of over $2 billion, and profits of $123 million. InterNorth began as Northern Natural Gas Company, organized in Omaha, Nebraska, in 1930. When InterNorth, with one of the nation’s premier pipeline networks with revenues of $7.5 billion in 1984, found itself the potential takeover target of corporate raiders, CEO Sam Segnar sought to buy out HNG, and a deal was announced in May 1985 in which InterNorth would acquire HNG for $2.4 billion. The arrangement stipulated that the merged entities would be known as HNG/InterNorth and be headquartered in Omaha with Segnar as chairman and CEO. However by 1986 Segnar had retired, Kenneth Lay was chairman and CEO, and the company was renamed Enron with corporate headquarters in Houston. The new company had the second largest pipeline network in the United States with over 36,000 miles of pipe stretching across the continent and north into Canada.
With a small business, like a sole proprietor, the boundaries of the entity are fairly clear, but as a business grows and acquires new assets and even whole entities, the lines can become blurred. That’s why it’s important, when looking at financial accounting information, to know exactly the scope of the information; to know which business entities are included and which are not. It’s also important to know if the business as reported is a viable entity, and not just something temporary. That’s the second underlying assumption of GAAP—that the entity being observed is a going concern.
What is the Going Concern Principle?
The going concern assumption under GAAP presumes that the economic entity will remain in operation for the foreseeable future and has no plans to wrap up operations, because an entity that is going bankrupt or is contemplating ending operations is probably not a good investment.
Enron
In order to hide the reality of the failing commodities trading from investors and creditors, Enron creatively adopted accounting practices from other industries, all GAAP compliant, such as mark-to-market accounting. For the most part, mark-to-market revenue recognition was used by investment firms in order to adjust securities from cost to current market value, but Enron was using the practice to report revenues that hadn’t even been earned yet.
For instance, in January 2000 Enron announced its entry into the broadband fiber optic business, citing this move as a natural extension of the company’s services. However, the timing was bad. The supply of fiber optic capacity far exceeded demand and prices were actually dropping around the country. In retrospect, analysts estimate that Enron lost over $1 billion in its broadband venture. Even so, Enron accountants managed to record a profit of over $100 million by reporting a deal with Blockbuster that, in reality, never produced a single dollar of revenue.
Even as Enron secretly plunged toward bankruptcy, the stock rose 56 percent in 1999 and another 87 percent in 2000. And where were the outside auditors in all this? Arthur Anderson, the accounting firm hired by Enron to audit the annual financial statements, also held large consulting contracts with the company that impaired its independence and ultimately resulted in a clean audit opinion. In reality, Enron was teetering on the edge of bankruptcy. On December 2, 2001, Enron filed for protection under United States bankruptcy laws, at that time the largest such filing of its kind in United States history. Stock prices that year fell from a high of over $90 per share to nothing.
Practice Questions


25.4: Immunodeficiency
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- Last updated
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Learning Objectives
- Compare the causes of primary and secondary immunodeficiencies
- Explain why patients with chronic granulomatous disease are especially susceptible to bacterial infections
- Explain why individuals with IgA deficiency are susceptible to respiratory and GI infections
- Describe treatments for primary and secondary immunodeficiencies
- Explain why secondary immunodeficiencies can sometimes be reversed
Immunodeficiencies are inherited (primary) or acquired (secondary) disorders in which elements of host immune defenses are either absent or functionally defective. In developed countries, most immunodeficiencies are inherited, and they are usually first seen in the clinic as recurrent or overwhelming infections in infants. However, on a global scale, malnutrition is the most common cause of immunodeficiency and would be categorized as an acquired immunodeficiency. Acquired immunodeficiencies are more likely to develop later in life, and the pathogenic mechanisms of many remain obscure.
Primary Immunodeficiency
Primary immunodeficiencies , which number more than 250, are caused by inherited defects of either nonspecific innate or specific adaptive immune defenses. In general, patients born with primary immunodeficiency (PI) commonly have an increased susceptibility to infection. This susceptibility can become apparent shortly after birth or in early childhood for some individuals, whereas other patients develop symptoms later in life. Some primary immunodeficiencies are due to a defect of a single cellular or humoral component of the immune system; others may result from defects of more than one component. Examples of primary immunodeficiencies include chronic granulomatous disease, X-linked agammaglobulinemia, selective IgA deficiency, and severe combined immunodeficiency disease.
Chronic Granulomatous Disease
The causes of chronic granulomatous disease (CGD) are defects in the NADPH oxidase system of phagocytic cells, including neutrophils and macrophages, that prevent the production of superoxide radicals in phagolysosomes. The inability to produce superoxide radicals impairs the antibacterial activity of phagocytes. As a result, infections in patients with CGD persist longer, leading to a chronic local inflammation called a granuloma. Microorganisms that are the most common causes of infections in patients with CGD include Aspergillus spp., Staphylococcus aureus , Chromobacterium violaceum , Serratia marcescens , and Salmonella typhimurium .
X-Linked Agammaglobulinemia
Deficiencies in B cells due to defective differentiation lead to a lack of specific antibody production known as X-linked agammaglobulinemia . In 1952, Ogden C. Bruton (1908–2003) described the first immunodeficiency in a boy whose immune system failed to produce antibodies. This defect is inherited on the X chromosome and is characterized by the absence of immunoglobulin in the serum; it is called Bruton X-linked agammaglobulinemia (XLA). The defective gene, BTK, in XLA is now known to encode a tyrosine kinase called Bruton tyrosine kinase (Btk). In patients whose B cells are unable to produce sufficient amounts of Btk, the B-cell maturation and differentiation halts at the pre-B-cell stage of growth. B-cell maturation and differentiation beyond the pre-B-cell stage of growth is required for immunoglobulin production. Patients who lack antibody production suffer from recurrent infections almost exclusively due to extracellular pathogens that cause pyogenic infections: Haemophilus influenzae , Streptococcus pneumoniae , S. pyogenes , and S. aureus . Because cell-mediated immunity is not impaired, these patients are not particularly vulnerable to infections caused by viruses or intracellular pathogens.
Selective IgA Deficiency
The most common inherited form of immunoglobulin deficiency is selective IgA deficiency, affecting about one in 800 people. Individuals with selective IgA deficiency produce normal levels of IgG and IgM, but are not able to produce secretory IgA. IgA deficiency predisposes these individuals to lung and gastrointestinal infections for which secretory IgA is normally an important defense mechanism. Infections in the lungs and gastrointestinal tract can involve a variety of pathogens, including H. influenzae , S. pneumoniae , Moraxella catarrhalis , S. aureus , Giardia lamblia , or pathogenic strains of Escherichia coli .
Query \(\PageIndex{1}\)
Severe Combined Immunodeficiency
Patients who suffer from severe combined immunodeficiency (SCID) have B-cell and T-cell defects that impair T-cell dependent antibody responses as well as cell-mediated immune responses. Patients with SCID also cannot develop immunological memory, so vaccines provide them no protection, and live attenuated vaccines (e.g., for varicella-zoster, measles virus, rotavirus, poliovirus) can actually cause the infection they are intended to prevent. The most common form is X-linked SCID, which accounts for nearly 50% of all cases and occurs primarily in males. Patients with SCID are typically diagnosed within the first few months of life after developing severe, often life-threatening, opportunistic infection by Candida spp., Pneumocystis jirovecii , or pathogenic strains of E. coli .
Without treatment, babies with SCID do not typically survive infancy. In some cases, a bone marrow transplant may successfully correct the defects in lymphocyte development that lead to the SCID phenotype, by replacing the defective component. However, this treatment approach is not without risks, as demonstrated by the famous case of David Vetter (1971–1984), better known as “Bubble Boy” (Figure \(\PageIndex{1}\)). Vetter, a patient with SCID who lived in a protective plastic bubble to prevent exposure to opportunistic microbes, received a bone marrow transplant from his sister. Because of a latent Epstein-Barr virus infection in her bone marrow, however, he developed mononucleosis and died of Burkitt lymphoma at the age of 12 years.
Query \(\PageIndex{1}\)
Secondary Immunodeficiency
A secondary immunodeficiency occurs as a result an acquired impairment of function of B cells, T cells, or both. Secondary immunodeficiencies can be caused by:
- Systemic disorders such as diabetes mellitus, malnutrition, hepatitis, or HIV infection
- Immunosuppressive treatments such as cytotoxic chemotherapy, bone marrow ablation before transplantation, or radiation therapy
- Prolonged critical illness due to infection, surgery, or trauma in the very young, elderly, or hospitalized patients
Unlike primary immunodeficiencies, which have a genetic basis, secondary immunodeficiencies are often reversible if the underlying cause is resolved. Patients with secondary immunodeficiencies develop an increased susceptibility to an otherwise benign infection by opportunistic pathogens such as Candida spp., P. jirovecii , and Cryptosporidium .
HIV infection and the associated acquired immunodeficiency syndrome (AIDS) are the best-known secondary immunodeficiencies. AIDS is characterized by profound CD4 T-cell lymphopenia (decrease in lymphocytes). The decrease in CD4 T cells is the result of various mechanisms, including HIV-induced pyroptosis (a type of apoptosis that stimulates an inflammatory response), viral cytopathic effect, and cytotoxicity to HIV-infected cells.
The most common cause of secondary immunodeficiency worldwide is severe malnutrition, which affects both innate and adaptive immunity. More research and information are needed for the more common causes of secondary immunodeficiency; however, the number of new discoveries in AIDS research far exceeds that of any other single cause of secondary immunodeficiency. AIDS research has paid off extremely well in terms of discoveries and treatments; increased research into the most common cause of immunodeficiency, malnutrition, would likely be as beneficial.
An Immunocompromised Host
Benjamin, a 50-year-old male patient who has been receiving chemotherapy to treat his chronic myelogenous leukemia (CML), a disease characterized by massive overproduction of nonfunctional, malignant myelocytic leukocytes that crowd out other, healthy leukocytes, is seen in the emergency department. He is complaining of a productive, wet cough, dyspnea, and fatigue. On examination, his pulse is 120 beats per minute (bpm) (normal range is 60–100 bpm) and weak, and his blood pressure is 90/60 mm Hg (normal is 120/80 mm Hg). During auscultation, a distinct crackling can be heard in his lungs as he breathes, and his pulse-oximeter level (a measurement of blood-oxygen saturation) is 80% (normal is 95%–100%). He has a fever; his temperature is 38.9 °C (102 °F). Sputum cultures and blood samples are obtained and sent to the lab, but Benjamin goes into respiratory distress and dies before the results can be obtained.
Benjamin’s death was a result of a combination of his immune system being compromised by his leukemia and his chemotherapy treatment further weakening his ability to mount an immune response. CML (and leukemia in general) and corresponding chemotherapy cause a decrease in the number of leukocytes capable of normal function, leading to secondary immunodeficiency. This increases the risk for opportunistic bacterial, viral, protozoal, and fungal infections that could include Staphylococcus , enteroviruses, Pneumocystis , Giardia, or Candida . Benjamin’s symptoms were suggestive of bacterial pneumonia, but his leukemia and chemotherapy likely complicated and contributed to the severity of the pneumonia, resulting in his death. Because his leukemia was overproducing certain white blood cells, and those overproduced white blood cells were largely nonfunctional or abnormal in their function, he did not have the proper immune system blood cells to help him fight off the infection.
| Disease | Effect on Immune Function | Outcomes | |
|---|---|---|---|
| Primary immunodeficiencies | Chronic granulomatous disease | Impaired killing of bacteria within the phagolysosome of neutrophils and macrophages | Chronic infections and granulomas |
| Selective IgA deficiency | Inability to produce secretory IgA | Predisposition to lung and gastrointestinal infections | |
| Severe combined immunodeficiency disease (SCID) | Deficient humoral and cell-mediated immune responses | Early development of severe and life-threatening opportunistic infections | |
| X-linked agammaglobulinemia | Flawed differentiation of B cells and absence of specific antibodies | Recurrent infections almost exclusively due to pathogens that cause pyogenic infections | |
| Secondary immunodeficiencies | Immunosuppressive therapies (e.g., chemotherapy, radiotherapy) | Impaired humoral and/or cell-mediated immune responses | Opportunistic infections, rare cancers |
| Malnutrition | Impaired humoral and/or cell-mediated immune responses | Opportunistic infections, rare cancers | |
| Viral infection (e.g., HIV) | Impaired cell-mediated immune responses due to CD4 T-cell lymphopenia | Opportunistic infections, rare cancers |
Query \(\PageIndex{1}\)
Key Concepts and Summary
- Primary immunodeficiencies are caused by genetic abnormalities; secondary immunodeficiencies are acquired through disease, diet, or environmental exposures.
- Primary immunodeficiencies may result from flaws in phagocyte killing of innate immunity, or impairment of T cells and B cells.
- Primary immunodeficiencies include chronic granulomatous disease, X-linked agammaglobulinemia, selective IgA deficiency, and severe combined immunodeficiency disease.
- Secondary immunodeficiencies result from environmentally induced defects in B cells and/or T cells.
- Causes for secondary immunodeficiencies include malnutrition, viral infection, diabetes, prolonged infections, and chemical or radiation exposure.


Key Takeaways
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The process of creating a script typically involves running the processing steps in the EEGLAB/ERPLAB GUI, copying the commands from the history into a script, and adding a loop.
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You will save yourself a lot of time and pain in the long run by using intrinsically meaningful variable names, including lots of comments, and defining all key values as variables at the top of the script.
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It’s almost always better to write a sequence of relatively simple scripts rather than one large script that does everything. This makes errors less likely, makes errors easier to find, and gives you more flexibility.
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You should make extensive use of the GUI the first time your process the data from a given participant. This allows you to detect problems in the data, set participant-specific parameters (e.g., for artifact rejection and correction), and make sure that everything is working properly. Once you’ve gone through the data in this manner, you should reprocess the data with your scripts (which helps avoids errors that can occur in manual processing).
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You can learn a lot by getting example scripts from other people, but don’t apply those scripts to your own data unless you fully understand every line of code.
References
Emerson, R. W. (1841).
Self-Reliance
. Lulu Press.
Luck, S. J., Stewart, A. X., Simmons, A. M., & Rhemtulla, M. (2021). Standardized measurement error: A universal metric of data quality for averaged event-related potentials.
Psychophysiology
,
58
, e13793.
https://doi.org/10.1111/psyp.13793
Rosenbaum, D. A., Vaughan, J., & Wyble, B. (2014).
MATLAB for Behavioral Scientists
(2nd Edition). Routledge.
Rossion, B., & Caharel, S. (2011). ERP evidence for the speed of face categorization in the human brain: Disentangling the contribution of low-level visual cues from face perception.
Vision Research
,
51
(12), 1297–1311.
https://doi.org/10.1016/j.visres.2011.04.003


2.8: Worksheet Answers
1. Correct the way these scientific names are written.
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- Felis catus or Felis cattus (domestic cat)
- Mus musculus or Mus musculus (mouse)
- Rattus norvegicus or Rattus norvegicus (brown rat)
- Canis familiaris or Canis familiaris (domestic dog)
- Gallus gallus or Gallus gallus (chicken)
- Echinococcus granulosus, Linnaeus, 1758 or Echinococcus granulosus , Linnaeus, 1758 (hydatid tapeworm). Correct already
- Rana temporalis or Rana temporalis (frog)
2. The rules for writing scientific names are:
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- There are always two parts to the name
- The name is in Latin
- The first part of the name has a capital first letter
- The second part of the name is all lower case
- The name is written in italics or underlined
3. Place these organisms in one of the five Kingdoms. (ie Plant (P), Animal (A), Fungus (F), Bacterium (B), Single celled organisms (S)).
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- Mushroom F
- Octopus A
- Mycobacterium bovis (TB bacterium) B
- Pine tree P
- Plasmodium vivax (malaria parasite) S
- Flea A
- Seaweed P
- Elephant A
- Toenail - not a living organism
4. Which of these belong in the Animal Kingdom?
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- Carnivorous plant - No it is a plant
- Killer whale - Yes
- Jellyfish - Yes
- Tapeworm - Yes
- Ringworm – No, it is a fungus
- Earthworm Yes
- Frog - Yes
5. Place the following Vertebrates in the right Class (i.e. Fish (F), Amphibian (A), Reptile (R), Bird (B) or Mammal (M))
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- Toad A
- Hammerhead shark F
- Opossum M
- Rattle snake R
- Emu B
- Tortoise R
- Ferret M
- Platypus M
- Tree frog A
- Flounder F
6. Fill in the blanks in the table below.
| Characteristic/Class | FISH | AMPHIBIAN | REPTILE | MAMMAL | BIRD |
|---|---|---|---|---|---|
| HABITAT | Water | Water/land | Land | Land and water | Air |
| RESPIRATION | Gills | Gills & lungs | Lungs | Lungs | Lungs |
| LIMBS | Fins | Weak legs | Legs | Legs | Wings |
| SKIN | Porous, wet | Porous | Waterproof, dry | Waterproof with hair | Waterproof with feathers |
| REPRODUCTION |
In water,
thin shelled eggs |
In water, thin shelled eggs |
On land,
thicker shelled, waterproof eggs |
Internal gestation
in uterus |
Thicker shelled,
waterproof eggs, on land |
| FERTILISATION | External | External | Internal | Internal | Internal |
| TEMPERATURE CONTROL |
Cold blooded
(poikilothermic) |
Cold blooded
(poikilothermic) |
Cold blooded
(poikilothermic) |
Warm blooded
(homoiothermic) |
Warm blooded
(homoiothermic) |
7. Mammals are divided into 3 groups, the Monotremes (Mono), Marsupials (Mar) and Mammals proper (MP). Place the following into one of these groups.
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- Mouse MP
- Pouched mouse Mar
- Duck billed platypus Mono
- Guinea pig Mp
- Wombat Mar
- Aardvark MP
- Koala Mar
- Opossum Mar
- Ant eater MP
- Wolf MP
- Tasman wolf Mar
8.  Place the following categories used in the classification of animals in the correct order i.e. From largest group to smallest.
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- Kingdom, Phylum. Class, Order, Family, Genus, Species,
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10. Two animals belong to the same species if they can mate and produce fertile offspring.


7.6B: Ulna and Radius (The Forearm)
The forearm contains two bones, the radius and the ulna.
- Discuss the radius and ulna
Key Points
- The radius and the ulna are long, slightly curved bones that lie parallel from the elbow, where they articulate with the humerus, to the wrist, where they articulate with the carpals.
- The radius is located laterally, near the thumb, and the ulna medially, near the little finger. The radius and the ulna have a styloid process at the distal end; they are also attachment sites for many muscles.
- The radius is smaller than the ulna.
Key Terms
- radius : One of two forearm bones, it is located laterally to the ulna.
- ulna : One of two forearm bones, it is located medially to the radius.
The forearm : The radius and ulna are the bones of the forearm.
The forearm contains two bones—the radius and the ulna—that extend in parallel from the elbow, where they articulate with the humerus to the wrist, where they articulate with the carpals. The space between the two bones is spanned by the interosseous membrane.
The Ulna
Anatomically, the ulna is located medially to the radius, placing it near the little finger. The ulna is slightly larger than the radius.
Proximally, there are five key regions of the ulna:
- The olecranon is a projection of bone that extends proximally from the ulna.
- The triceps brachii muscle attaches to the ulna superiorly.
- The cornoid process, together with the olecranon, forms the trochlear notch where it articulates with the trochlea of the humerus.
- Laterally to the trochlear notch lies the radial notch, which articulates with the head of the radius to form the proximal radioulnar joint.
- Immediately distal to the coronoid process is the tuberosity of ulna, to which the brachialis muscle attaches.
The shaft of the ulna is triangular and numerus muscles involved in pronation and flexion of the forearm attach to its surface.
Distally, the ulna is much smaller and terminates with a rounded head that articulates with the ulnar notch of the radius to form the distal radioulnar joint. The styloid process of the ulna extends distally and is the site of attachment for ligaments found in the wrist.
The Radius
Anatomically, the radius is located laterally to the ulna placing it near the thumb. The radius is slightly smaller than the ulna and pivots around the ulna to produce movement at the proximal and distal radioulnar joints.
Proximally, the radius terminates with a disk-shaped head that articulates with the capitulum of the humerus and the radial notch of the ulna. Immediately below the head lies the radial tuberosity to which the biceps brachii attaches. As with the ulna, the shaft of the radius is triangular in shape and numerous muscles, including the protonator teres, attach to it.
Distally the radius expands, medially the ulnar notch articulates with the head of the ulnar. Immediately adjacent to the ulnar notch, the radius articulates with the scaphoid and lunate carpal bones to form part of the wrist.


1: Introduction to Retailing Last updated Save as PDF Page ID 44959 1.1: Why It Matters- Introduction to Retailing 1.2: Introduction to Retailing 1.3: Retailing 1.4: Supply Chains 1.5: Challenges in Retailing 1.6: Introduction to the Evolution of Retail 1.7: Historical Changes in Retail 1.8: Information Systems in Retail 1.9: Adaptation in Retail 1.10: Introduction to Careers in Retail 1.11: Key Roles in a Retail Business 1.12: Why Working Retail Is Tough 1.13: Retail Management Requirements 1.14: Skills of a Retail Manager 1.15: Introduction to Strategic Planning in Retail Management 1.16: Microenvironment vs. Macroenvironment 1.17: Strategic Planning in Retail 1.18: The Retail Mix 1.19: The Retailing Concept 1.20: Putting It Together- Introduction to Retailing 1.21: Discussion- Introduction to Retailing


12.14: Reading- Integrated Supply Chain Management
As the importance of managing the supply chain well has increased, companies have acknowledged that they must manage the supply chain as a complete system and treat it as an integrated function. When an organization takes an integrated approach, it is recognizing that it cannot manage each part of the supply chain as an independent function, but instead needs to understand and manage the connections and interdependencies.
Within the supply chain organization, this means that sourcing, demand planning, inventory planning, warehousing, logistics, and order-fulfillment functions must work together. The rise of supply chain software tools that bring this data and information together in one place is just one indicator of an increasingly integrated focus. Also, many organizations previously had these functions spread between different organizations with little opportunity to interact. Today, most large organizations have an integrated supply chain function with a common management team and common objectives.
Beyond the work occurring within the supply chain organization, there are important connections to marketing, finance, and manufacturing. Marketing plays a direct role in creating the demand forecast and defining the product and delivery expectations for customers. These must be reviewed with the supply chain team so that everyone knows what needs to be achieved, and when that isn’t possible, adjustments can be made and communicated to customers early. The integration with finance is necessary to ensure that investments are budgeted correctly and inventory is accounted for accurately. Manufacturing is often most heavily affected by decisions and requirements of the supply chain team, as they are counting on having an adequate supply and must meet delivery time lines to keep customer commitments.
As with many complex organizational challenges, this integration works best when there are clear objectives that are set across the organizations, a common view of the data (which identify opportunities for improved performance), and clear, frequent communication about potential issues and needs. This enables all of the organizations to focus on delivering value to customers and achieving the company mission.
Contributors and Attributions
- Integrated Supply Chain Management. Provided by : Lumen Learning. License : CC BY: Attribution
- Network. Provided by : Pixabay. Located at : pixabay.com/en/network-ball-about-structure-441686/. License : CC0: No Rights Reserved


5.2: The Treme Moral Economy
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- Vicki Mayer
- University of California Press
In 2013, Louisiana surpassed California as the primary location for the production of major Hollywood motion pictures. 3 The state, one of the poorest in terms of the per capita poverty rate and median income, also outpaced Hollywood film shooting in other countries, including Canada and Ireland. This locational outsourcing, often derided as runaway production, has been a point of pride in Louisiana. There, media producers and policymakers alike have seized on film jobs as a cornerstone in the economic renewal of the entire Gulf Coast after a series of devastating environmental disasters, including two hurricanes and an oil spill, destabilized the political and economic infrastructure of the region. The city of New Orleans, which evacuated its entire population of nearly half a million people in 2005 after Hurricane Katrina and subsequently lost many longtime residents, has depended heavily on the growing film economy to bring new migrants and jobs. A 2012 Forbes article summarized the recent political economy: “Aggressive tax incentives have also been beneficial in luring new recruits, entrepreneurs, and large business to New Orleans. In 2002, a foundation for a new film industry had been established with a tax credit program for movies produced in the state. However, it wasn’t until after Katrina that more production crews committed to continuing their work with Louisiana, and quickly saw the benefits of working in the region. In addition, the productions were pumping millions of dollars into the city’s recovering economy, and providing jobs to those who wanted to get into the industry.” 4 Ten years after the storm, the city still acknowledges the scars of Katrina—press articles still refer to the “post-K” era—while touting the power of the most generous film tax incentives in the United States to aid future recovery.
In this context, a television series that would focus on the city’s unique vernacular value and cultural resilience in the post-K era drew special attention. The auteur television producers David Simon and Eric Overmyer said they had wanted to create a program about New Orleans music long before the storm, but that the disaster brought a sudden moral imperative to make a general concept into a story. “Even ordinary scenes played out against a backdrop of this city three months after the storm take on an incredibly different dynamic. An ordinary scene . . . is about something much bigger,” said Simon, while waiting for the green light from the HBO network in 2009. Arguing for the symbolic importance of viewers witnessing a second-line parade in the months after the storm, Simon explained, “Just as a visual tableau, that’s an incredible statement of human endeavor. And you place it in the context of all the political (news) and all the problems and all of the dystopic things that have happened post-Katrina—if you can’t (make) a story of that, shame on you.” 5 Within weeks, Fee Nah Nee, the local production company for Treme , would begin the process of certifying the applicable tax credits for producing the series.
For four years, Treme indexed the tight imbrication between the film economy and New Orleans through a program focused on ordinary life and an extraordinary local culture. Music, food, and public performance took center stage in the weekly narrative, which broadcast via the subscriber channel for three and a half seasons. Beyond this, the program’s producers were active in charity and volunteer efforts dedicated to local musicians and the musical cultures of the region. Production crews threw block parties in some of its affected shooting locations and helped host screening parties for residents who could not afford premium cable television service. Newspaper columns deciphered the careful cultural details and historical referents stitched into the story lines, and social media organized fans to participate in the interpretative community. From this base of avid viewers and admirers, Treme set out to hire local residents as part of its ethos. The hiring director, who had worked as a local on the Baltimore set of the earlier Simon/Overmyer collaboration, The Wire , told me he was always irked by film companies that shot in his hometown but hired outsiders. Treme would aim to hire residents, he explained, touting his efforts to support a local training clinic for film crew certification, because “it’s the right thing to do.”
It was also the most economical thing to do. Louisiana residents received an extra 5 percent in state tax credits, bringing their total discount to 35 percent of the budget. Locals do not have to be housed in hotels. They go home each day without a need for a per diem or transportation. On the set, the same director told me that the local hire brought added value to the decision-making process. They have “natural knowledge” that streamlines the production schedule. He said, “They know the Teamsters, and the bureaucrats, and also the residents. So they don’t mind as much when you invade their neighborhood.” In the battle to beat the budget, he said locals helped “win the hearts and minds” of the citizens.
This odd pairing of the ethically right and the instrumentally efficient was the labor strategy in Treme ’s moral economy. Mark Banks sees moral economies as a counterweight to the alienating and individuating tendencies of marketplaces. 6 In them, the basis of the exchange relation is founded in a social relationship that recognizes the worker as a unique individual rather than an object for exploitation. By offering to restore a measure of recognition to workers’ identities and experiences, these exchange economies seem to thrive in precarious settings that have already been ravaged by the worst excesses of neoliberal policies. In New Orleans, for example, privatization of recovery efforts shunted the responsibility for basic human services onto private corporations, which could then monetize relief and promote it as a form of corporate social responsibility. 7 Media industries since 2005 were at the forefront of using Katrina storylines to generate both advertising revenues and corporate goodwill, often based on their ability to harness and channel the free labor or charity of others. This was particularly apparent in a spate of reality television and talk show programs that frequently promised to improve the well-being of the ordinary people brought into the production. 8 These genres often claimed that their staff and crew were part of a family that left the local population better off. In the meantime, the programs were effective at cutting production costs by appropriating local settings and enrolling local residents, often in the form of volunteers. Although Treme followed this trajectory of corporate social responsibility, it also went beyond in imagining a more sustained investment in the lives of New Orleans’s creative workers than a single television episode or promotional event.
To their call to help New Orleans through media labor, extras responded in droves.


3.7: Chapter 3 Homework Problems
An 18-inch shelf is supported by a pin joint at point A, and a cable at point B. The shelf itself has a weight of 60 lbs. If we want the net moment about point A to be zero, what should the tension in the cable be?
- Solution
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\(T = 52.30 \, lbs\)
What is the moment the force shown below exerts about Point A? About Point B?
Hint: use Varginon's Theorem.
- Solution
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\(M_A = 10.88 \, kNm \)
\(M_B = 21.02 \, kNm\)
You are attempting to rotate a heavy table about the base of one leg at point O and are going to exert a 100-lb force at the opposite end. Person A recommends pulling straight up, while person B recommends pulling up at 30° from vertical. What would be the moment about point O, in inch-pounds, in either case?
- Solution
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\(M_{AO} = 6000 \, \text{in-lbs} \)
\(M_{BO} = 6996.15 \, \text{in-lbs}\)
Determine the moment vectors that each of the three tension forces in the diagram below exerts about the origin point O. Provide the answers in vector form with units.
- Solution
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\(M_{AO} = [0, \, -400, \, 0] \, Nm\)
\(M_{BO} = [-300, \, 0, \, 0] \, Nm\)
\( M_{CO} = [300, \, 0, \, 0] Nm\)
You exert a 50-lb force on the side of a fridge as shown below. Assuming the fridge is sitting on a rough surface and not moving, what is the magnitude of the moment exerted by the couple consisting of the pushing force and the friction force?
- Solution
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\(M = -100 \text{ft-lbs}\)
A space station consists of a large ring that spins in order to provide an artificial gravity for the astronauts in the station. To start the station spinning, a pair of thrusters is attached to the outside of the ring, each pointing in opposite directions as shown below.
a) If we want to exert a 10 kN-m moment with the thrusters, and the ring has a diameter of 45 meters, what thrust force should each thruster produce?
b) If we were to use the same thrusters on a 60-meter diameter ring, what moment would they exert?
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a) \(F_{thruster} = 222.22 \, N\)
b) \(M_{thruster} = 13.33 \, kNm\)
A 60-N force is applied in the \(yz\) plane, 40° from the \(y\) direction, on an L-shaped bar as shown below.
a) What is the moment vector this force exerts about point O?
b) What is the overall magnitude of the moment about point O?
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\(M_O = [-11.49, \, -11.57, \, 13.79] \, Nm\)
\(|M| = 21.36 \, Nm\)
What is the moment that the force shown in the diagram exerts about point O? About the axis of the cylindrical shaft (the \(y\)-axis)?
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\(M_O = [16484, \, 17046, \, -20979] \, in-lbs\)
\(M_y = 17046 \, in-lbs\)
The diving board shown below is supported by a pin joint at A and frictionless support at B. A 150-lb diver is standing at the end of the board. Determine the reaction forces acting on the diving board at points A and B.
- Solution
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\(F_{AX} = 0\)
\(F_{AY} = -450 \, lbs\)
\(F_{BY} = 600 \, lbs\)
A simplified crane is shown lifting a 400-kg load. The crane is supported by a pin joint at A, and a cable at B. Assuming the crane arm is in equilibrium, what are the reaction forces at A and the tension at B?
- Solution
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\(F_{AX} = 9352.9 \, N\)
\(F_{AY} = 3924 \, N\)
\(T_{B} = 9352.9 \, N\)
An 8-foot ladder sits propped up against a wall at a 60-degree angle as shown below. It has a weight of 50 lbs acting at its center point and supports a 120-lb woman 6 feet from the bottom. Assume that friction acts at the bottom of the ladder, but not the top. What are the normal forces acting at the bottom and top of the ladder, and what is the friction force acting at the bottom of the ladder?
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\(F_{N \, Top} = 66.4 \, lbs\)
\(F_{N \, Bottom} = 170 \, lbs\)
\(F_f = 66.4 lbs\)
An SUV with a weight of 4200 lbs and a center of mass located as shown below is parked pointed downhill on a 10-degree incline. The parking is engaged, locking up the back wheels but not the front wheels. What is the expected normal force at the front wheels, the expected normal force at the back wheels, and the expected friction force at the back wheels assuming the SUV does not slip?
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\(F_f = 729.3 \, lbs\)
\(F_{N \, front} = 3000.6 \, lbs\)
\(F_{N \, back} = 1135.6 \, lbs\)
A cart with a mass of 3500 kg sits on an inclined surface as shown below. Determine the reaction forces acting on each wheel of the cart as well as the tension in the cable supporting the cart.
- Solution
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\(T = 21786 \, N\)
\(F_A = 7222 \, N; \, F_B = 35925 \, N\)
The lighting rig above a stage consists of two 100-lb, uniform beams joined together in a T as shown below (assume the weight acts in the center of each beam). The rig is supported by three cables at A, B, and C. Determine the tension in each of the three cables.
- Solution
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\(T_A = 50 \, lbs; \, \, T_B = 66.7 \, lbs; \, T_C = 83.3 \, lbs\)
A 9-meter-long pole with a mass of 100 kg is suspended horizontally, 4 meters from the ceiling with three cables as shown below. Assuming the center of mass of the pole is at the center point of the pole, what is the expected tension in each of the three cables?
- Solution
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\(T_A = 357.66 \, N; \, T_B = 357.66 \, N; \, T_C = 408.75 \, N\)


20.5: Modeling circuits with capacitors
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review topics
- Section 18.5 on capacitors.
So far, we have modeled circuits where the current does not change with time. When a capacitor is included in a circuit, the current will change with time, as the capacitor charges or discharges. The circuit shown in Figure \(\PageIndex{1}\) shows an ideal battery 1 ( \(\Delta V\) ), in series with a resistor ( \(R\) ), a capacitor ( \(C\) , two vertical bars) and a switch ( \(S\) ) that is open.
When the switch is open, current cannot flow through the circuit. If we assume that the capacitor has no charge on it, once we close the switch, current will start to flow and charges will accumulate on the capacitor. Electrons will leave the negative terminal of the battery, flow through the resistor and accumulate on the left side of the capacitor, which acquires a negative charge. This pushes electrons off of the right hand side of the capacitor, which then becomes positively charged. The electrons from the positive side of the capacitor then flow into the positive side of the battery, completing the circuit.
Eventually, the charges on the capacitor will build up to a point were they prevent any further flow of current. Once the left side of the capacitor is at the same potential as the left side of the battery, current will cease to flow. That is, eventually, the potential difference across the capacitor will be equal to that across the battery, and we can think of this as a circuit used to charge a capacitor. The current is high when the switch is first opened, but eventually goes down to zero as the capacitor charges. The current is thus time-dependent.
We can model this simple circuit (with the switch closed) using Kirchhoff’s loop rule. The sum of the voltages across each component must sum to zero:
\[\begin{aligned} \Delta V - IR - \frac{Q}{C} = 0\end{aligned}\]
where we used the fact that the charge, \(Q\) , on a capacitor is related to the potential difference, \(\Delta V_C\) , across the capacitor by \(Q=C\Delta V_C\) . The current, \(I\) , is the rate at which charges flow through the circuit, and is thus equal to rate at which charges accumulate on the capacitor:
\[\begin{aligned} I=\frac{dQ}{dt}\end{aligned}\]
Substituting this into the loop equation, we obtain a separable differential equation for the charge on the capacitor as a function of time, \(Q(t)\) :
\[\begin{aligned} \Delta V - IR - \frac{Q}{C} &= 0\\[4pt] \Delta V - \frac{dQ}{dt}R - \frac{Q}{C} &= 0\\[4pt] \Delta V - \frac{Q}{C} &= \frac{dQ}{dt}R\\[4pt] C\Delta V - Q &= RC\frac{dQ}{dt}\\[4pt] \therefore \frac{dt}{RC}&=\frac{dQ}{C\Delta V - Q }\end{aligned}\]
This is similar to differential equations that we have solved previously (in fact, it is the same equation as in Example 6.2.3 where we looked at the effect of velocity-dependent drag). The solution to the equation, assuming that the switch is closed at \(t=0\) , is given by an exponential:
\[\begin{aligned} Q(t) = C\Delta V\left( 1 - e^{-\frac{t}{RC}} \right)\end{aligned}\]
Thus, the charge on the capacitor starts at zero when the switch is closed, and grows asymptotically until it reaches a value of \(Q=C\Delta V\) , which corresponds to the capacitor having the same potential difference across it as the battery. The value \(\tau=RC\) is called the “time constant” of the RC circuit, and corresponds to the time at which the capacitor will reach about \((1-e^{-1})=63\%\) of its maximal charge. The current as a function of time is given by:
\[\begin{aligned} I(t)=\frac{dQ}{dt}=\frac{\Delta V}{R}e^{-\frac{t}{RC}}\end{aligned}\]
and we can see that at time \(t=0\) the current is the same as if there were no capacitor present, and the current then decreases exponentially until it reaches zero.
Footnotes
1. The model still holds for a real battery, since the internal resistance of the battery can just be included into the resistance of the resistor, \(R\) .